PET (positron emission tomography) shows the brain's use of oxygen or sugar (glucose). As with SPECT, a very low, safe dose of a radioactive substance is injected into your arm and the scanner records how it travels through the brain. Not all types of PET scans look alike, but often different colors are used to show areas of higher or lower use of oxygen or sugar.

This test can help to identify the area of the brain where partial seizures arise.

It may be done in the period between seizures (the interictal period).

PET scans are expensive, and very few patients with epilepsy need them. Most insurance companies will pay for PET scans for patients who are being evaluated for epilepsy surgery.